Data are organized as follows :DefinitionsN_v : number of vertices in the graphN_e : number of edges (or segments) in the graphN_p : total number of discretization points N_p^i : number of discretization points for edge i (i in [0, N_e-1]). Note : N_p=Sum_i(N_p^i)File format## English comments on format are preceded by //define VERTEX N_vdefine EDGE N_edefine POINT N_pParameters {    ContentType "HxSpatialGraph"}VERTEX { float[3] VertexCoordinates } @1EDGE { int[2] EdgeConnectivity } @2EDGE { int NumEdgePoints } @3POINT { float[3] EdgePointCoordinates } @4POINT { float thickness } @5@1 #vertices coordinates (microns)// N_v lines : x,y,z coordinates of the N_v vertices (implicitly labelled from 0 to N_v-1), in micrometers.@2 # edges definition// N_e lines : definition of the N_e edges, with labels of starting and end vertex given for each edge@3 #number of points per edge// N_e lines : number of discretization points per edge (including starting and end vertex). //These data are useful for visual representation purposes, as field EdgePointCoordinates (@4) will contain the 3D coordinates of these points.@4 # points coordinates  (microns) // N_p lines : List of 3D coordinates of discretization points for each segment in turn, in micrometers : first are the N_p^0 points of the first edge, from start to end vertex as defined in section @2, ie coordinates of start vertex of the first segment, coordinates of the next N_p^0-2 discretization points, coordinates of end vertex of the first segment.Then, list of coordinates of discretization points for the second edge, from start to end vertex as defined in section @2, and so on and so forth.@5 # point thickness (microns)// N_p lines : local diameter of vascular segments, i.e. at the N_p points listed in section @4, in the same order.